Prior arts in fluid filtration are abundant and vast yet are all ordinary filtration blocking type devices. As they lack backwash function, increased rounds of filtration will increase blockage, and fluid will not be able to pass through as filtration accumulates. Hence, the machine will need to be stopped and be removed or replaced with a filtration core. This kind of working mode can no longer achieve successfully in the filtration mission on current mobility or machines. Traditional automatic filtration mechanisms that use mechanical or electrical signal to control backwash function are complex in assemblage and expensive in cost. Even though many medium to low capacity diesel engines may want to be applied with such mechanisms, when taking into account the cost and nature of the device, they may only abandon the utilization. In overcoming the above-mentioned defects, the inventor of the present application has invented an ‘Automatic purifying energy-saving filter’ in 2007 with Chinese patent application no. 200710066624.3. Basically the patent application has met the need of automatic filtration of fuels of the diesel engines. Through experimental uses in recent years, it is discovered that the fluid inversion structure of existing patent application still contains defects, wherein the speed and stability of fluid inversion body is low and insufficient, respectively. Further, the use scope is only limited to the automatic filtration of fuels of diesel engines. As the spinning of fluid inversion is not depended on any core shaft, collision with the surroundings occurs during the spinning and friction force is large without application of reflux back force washing power, thus affecting the stability of the work and frequency of the fluid inversion body spinning.